My experience with P&B shakes has been exactly like yours. I had to add an SWF (Salt-Water-Flush) to my routine to actually evacuate enough. Since that was the whole point of taking the P&B, I have decided to stop, give my body a rest, get whatever fiber and clay the shakes have left in my body OUT, and then find an alternative method of doing this cleanse.
Read through the forum...there are a variety of other methods out there that seem to work well for people.
I think our experience just goes to show that one size does not fit all!
Good luck finding the right protocol for yourself.